Communication devices such as wireless devices are also known as e.g. user equipments (UE), mobile terminals, wireless terminals, and/or mobile stations. Wireless devices are enabled to communicate wirelessly in a cellular communications network or wireless communication system, sometimes also referred to as a cellular radio system or cellular networks. The communication may be performed e.g. between two wireless devices, between a wireless device and a regular telephone and/or between a wireless device and a server via a Radio Access Network (RAN) and possibly one or more core networks, comprised within the cellular communications network.
Wireless devices may further be referred to as mobile telephones, cellular telephones, laptops, tablet computers or surf plates with wireless capability, just to mention some further examples. The wireless devices in the present context may be, for example, portable, pocket-storable, hand-held, computer-comprised, or vehicle-mounted mobile devices, enabled to communicate voice and/or data, via the RAN, with another entity, such as another wireless device or a server.
The cellular communications network covers a geographical area which is divided into cell areas, wherein each cell area being served by an network node. A cell is the geographical area where radio coverage is provided by the network node.
The wireless device may also be adapted to communicate via a Wireless Local Area Network (WLAN), sometimes referred to as a Wi-Fi network. The wireless device may connect to a network resource such as the Internet via a wireless network access point or access point of the WLAN.
In scenarios where a WLAN is co-deployed with a cellular communications network, the WLAN may be used to offload the cellular communications network to some extent, especially by passing those users to the WLAN which require high transport and/or radio resource usage due to the nature of their applications running.
With end-user Quality of Experience (QoE) in focus, it is crucial, that a proper and precise decision mechanism is used to make decisions on handovers between the cellular communications network and the WLAN, so that the end-user does not experience performance or throughput degradation after the handover. Accordingly, it is desirable that the QoE is at least on the same level after connecting to the WLAN as it was in the cellular communications network, before the handover. Handovers between networks of different types, such as between a cellular communications network and a WLAN, are often referred to as vertical handovers or vertical handoffs. The decision mechanism is sometimes referred to as a Call Admission Control (CAC) mechanism or a Connection Admission Control (CAC) mechanism.
The characteristics and usage of the WLAN is of great importance when providing a CAC mechanism to be used to make decisions on handovers from a cellular communications network to a WLAN. On a shared wireless channel operating with several modulation schemes, which may be the case in a WLAN, it is the channel occupation time per wireless device or application that matters. In existing solutions, the basis for the decision making mechanism does not provide enough information to enable a proper decision allowing a good capacity usage and performance in the cellular communications network and/or in the WLAN.